Today, thanks to the availability of high bandwidth connections and efficient data compression technologies, multimedia content can be transmitted with high quality. This generates new businesses and distribution models. Unfortunately, this also gives rise to a high level of piracy. For example, digital content (music, video and software game) can be pirated by users who make copies available to others or by insiders during production processes. Content protection technologies are intended to protect against content piracy. Their proper design and correct implementation are of central importance for the entertainment industry because the incurred losses can be huge.
An investigation on prevailing content protection technologies shows that there are many variants. However, what is common in each content distribution system is the basic security functionality. Indeed, before being written to a physical support or otherwise transmitted, content is usually encrypted by content providers. As a consequence, a required step prior to illegal distribution (namely, unauthorized distribution of content in peer-to-peer file sharing systems like Kazaa or E-mule or on physical media like DVDs) or illegal consumption (namely, unauthorized use of a content legally purchased) is extracting content from its protected form. Most of the time, this means recovering the content in clear. While existing content distribution systems address this issue, they do little or nothing to prevent a pirate or an end-user to divert them from their primary purpose.
Another form of piracy is that of illegal distribution involving bit-to-bit copies or device cloning. There exist techniques (disclosed for example in “Content Protection for Recordable Media: Introduction and Common Cryptographic Elements”, 2000. Revision 0.94, Intel Corporation, International Business Machines Corporation, Ltd. Matsushita Electric Industrial Co. and Toshiba Corporation—known as “CPRM”—or in “Advanced Access Content System (AACS): Introduction and Common Cryptographic Element”s, Feb. 17, 2006. Revision 0.91, Intel Corporation, International Business Machines Corporation, Ltd. Matsushita Electric Industrial Co., Toshiba Corporation, Microsoft Corporation, Sony Corporation, The Walt Disney Company, and Warner Bros—known as “AACS”—) based on a unique hardware ID making useless a number of duplication methods. The unique ID is typically encoded in or computed from the physical structure of a hardware material, generally the user's player or the physical support containing the multimedia content. These techniques have in common that this ID is located in a non-writable area of the hardware material. The unique hardware ID enables to securely bind the multimedia content to the player or physical support so that it can only be played using the corresponding player or the corresponding support. Other concurrent techniques, disclosed for example by Claudine Conrado, Franck Kamperman, Geert Jan Schrijen and Willem Jonker in “Privacy in an identity-based DRM system” (in Proceedings of the 14th International Workshop on Database and Expert Systems Applications (DEXA '03), pages 389-395, IEEE Computer Society, 2003) or by Paul Koster, Franck Kamperman, Peter Lenoir and Koen Vrielink in “Identity-based DRM: Personal entertainment domain” (in Transactions on Data Hiding and Multimedia Security I, volume 4300 of Lecture Notes in Computer Science, pages 104-122, Springer-Verlag, 2006), are based on authorization certificates issued by content distributors where the certificate is linked to a unique user ID.
The inventors have found that current implementations may be used as a tool for distributing information in a variety of crimes including child pornography (content laundering) or violations of copyrights (content re-repackaging). Unauthorized users can exploit distribution systems because the security chain is not addressed as a whole.